While the Sapphire Radeon HD 4850 Toxic arrives with a 50MHz overclock on its RV770 core and just over a 100MHz boost on the video memory, it still can be pushed even further. The Samsung GDDR3 is underclocked by 100MHz and a few more megahertz can be squeezed out of the RV770 core especially with its high-end VF900 heatsink. Unfortunately, there is no OverDrive support through the Catalyst Linux driver yet. As a result, the graphics card cannot be overclocked on Linux. The video memory was detected by the AMD Catalyst Control Center as running at 1150MHz, though the documentation for this graphics card reflected an 1100MHz stock speed.
For this initial testing of the Sapphire Radeon HD 4850 Toxic we had run version 1.0.5 of the Phoronix Test Suite. The tests included Nexuiz, Doom 3, Quake 4, and X-Plane 9. When running these tests from within the Phoronix Test Suite we had the anti-aliasing level set at 8x and the anisotropic filtering set to 16x. We will be delivering additional benchmarks of this graphics card under Linux with an upcoming driver release.